Hessian Handiworks, designer of the Deciduan Couples/Conception HUD.

Since 2008, the Deciduan™ Couples HUD has been the most advanced conception/pregnancy system available.

It takes realism and role-play to a new level within Second Life™, and is meant to offer an affordable alternative to other systems, with a focus on both reality and configurability to fit many different role-play scenarios. It's also compatible with Xcite!(tm) genitals, though they're not required.